The inventive concept relates generally semiconductor memory devices. More particularly, the inventive concept relates to nonvolatile memory devices including multiple planes.
Semiconductor memory devices may be embodied using one or more semiconductor material including silicon (Si), germanium (Ge), gallium arsenide (GaAs), and indium phosphide (InP). Semiconductor memory devices may be classified as volatile and nonvolatile memory devices.
Volatile memory devices such as the Dynamic Random Access Memory (DRAM) and Static RAM (SRAM) lose stored data in the absence of applied power. In contrast, nonvolatile memory devices, such as the Electrically Erasable Programmable Read Only Memory (EEPROM) including flash memory, Ferromagnetic RAM (FRAM), Phase-change RAM (PRAM), and Magnetic RAM (MRAM), etc. Flash memory may be further classified as NOR type and NAND type.
Ongoing efforts to provide very dense memory cell integration per unit area of memory device have motivated research into nonvolatile semiconductor device configurations that include one or more three-dimensional (3D) structures. Some of these structures include so-called Cell Over Peri or COP structures in which a peripheral circuit is disposed in a material plane between another plane including a memory cell array and the underlying substrate. Hence, a COP structure may be used to integrate relatively more memory cells per unit area of the constituent semiconductor memory device by placing one or more peripheral circuit(s) adjacent to one or more of the four (4) sides of the memory cell area between the memory cell plane and the substrate.